The difficulties that have arisen with respect to a successful integration of Bohr's model of the atom into mechanics and electrodynamics have recently led to speculations that a failure of all of our space-time conceptions is involved rather than a mere inadequacy of physics. It seems highly doubtful that it might be possible to represent inneratomic occurrences in the form of space-time models. Comments of this kind have been made by Bohr¹ as well as Born, Jordan and Heisenberg² in connection with their matrix mechanics. Schrödinger's wave mechanics should be seen as the decisive step towards a solution of the problem of matter. His views on wave mechanics have given a profound new turn to the problem of the atom. Accordingly, it seems justified to investigate once and for all the epistemológica! aspects of the problem of the atom.